Hydrocephalus, familiarly known as water on the brain, is an affliction which affects many people, including children. One of the symptoms of this serious malady is increased fluid pressure on the brain of the victim, which, unless relieved, can result in excruciating pain, and can potentially cause brain damage to the victim.
Hydrocephalus causes a slow, continuous build-up of fluid pressure on the brain. More specifically, in a patient afflicted with hydrocephalus, excess body fluid (cerebral spinal fluid, or CSF) slowly and continuously accumulates in the ventricles of the brain. To extract the excess body fluid from in the ventricles of the brain and thereby relieve the fluid pressure on the brain, techniques, many of which are minimally-invasive, have been developed for establishing a pathway for fluid communication from the area of accumulated fluid to an area external to the cranial cavity.
As an example of one such minimally-invasive technique, a long, slender catheter known as a "shunt" is advanced through a small entry site in the skull of a patient who is afflicted with hydrocephalus, and a distal end segment of the shunt is positioned in one of the ventricles of the brain. The proximal end of the shunt is connected to a valve which regulates the flow of excess cerebral spinal fluid (CSF) out of the skull and into another body cavity, e.g., the peritoneum or venous system. In other words, the excess CSF in the skull is drained through the shunt, to permit the restoration of a normal pressure in the skull (i.e., to restore normal intercranial pressure).
Typically, a plurality of small holes are formed in the distal end segment of the shunt catheter, and fluid that accumulates in the ventricle enters the holes and drains through the shunt, thereby relieving the fluid pressure on the brain.
Unfortunately, the small holes in the distal end segment of the shunt can become clogged, thereby impeding the draining of excess fluid from the cranial cavity. More specifically, a portion of the brain known as the choroid plexus can grow into the holes of the distal end segment of the shunt and clog the holes. When this occurs, it is necessary to remove the shunt from the brain and replace the shunt with another unclogged shunt.
Accordingly, it is desirable to avoid positioning the shunt too near the choroid plexus, to avoid eventual clogging of the shunt. On the other hand, the holes of the shunt catheter must be positioned in a precise location (which varies depending upon the patient's condition) in the ventricle to ensure that the shunt will effectively drain excess CSF.
It is not simple, however, to precisely position the shunt so that it will effectively drain excess brain fluid, while remaining unclogged by the choroid plexus. This is largely because in most shunt placement procedures the surgeon cannot directly view the path of advancement of the shunt into the brain while advancing the shunt into the brain.
Instead, a magnetic resonance imaging scan or CT scan is performed to generate an image of the patient's brain, sometime prior to shunt placement. This image is subsequently displayed in the operating room during the shunt placement procedure, and the surgeon "eyeballs" correct placement of the shunt based upon the image previously generated by the scan. In other words, the surgeon advances the shunt into the patient's brain not by viewing a real-time image of the brain, but by periodically glancing at a still-life image of the brain that has been generated prior to surgery. Not surprisingly, accurate placement of a shunt under such conditions is not always performed optimally.
Accordingly, it is an object of the present invention to provide a device for positioning a shunt in a brain of a patient to relieve hydrocephalus. It is another object of the present invention to provide a device for presenting an image of the pathway of advancement of a shunt into the brain of a patient, during the placement procedure. It is a further object of the present invention to provide a device for positioning a shunt which is easy to use and cost-effective to manufacture.